1. Technical Field
The present invention relates to a fluorescent image acquisition and projection apparatus. More specifically, the present invention relates to a fluorescent image acquisition and projection apparatus for real-time visualization of an invisible fluorescent signal, which can visualize an invisible fluorescent signal generated from a target object (a tissue of a living body, a cell of a living body, or the like) and directly project a visualized fluorescent signal back onto a region of the target object where the invisible fluorescent signal is generated, thereby determining a fluorescence generation location with the naked eye.
2. Related Art
Application fields of a fluorescence phenomenon have expanded from chemical measurement to phenomenal technical implementation. Imaging technology and measuring technology have been developed in the fields of medical research and molecular biological experiments using fluorescent signals and fluorescent images. Recently, various materials which can generate fluorescent signals with various wavelengths have been developed and applied to clinical and preclinical researches all over the world. Food and Drug Administration (FDA) approved some of those materials in clinical applications. With the development of various materials that generate fluorescence, technology for analyzing in vivo functions by using various light sources have been developed because fluorescent signals have a poor signal to noise ratio (SNR) and have the desirable penetration power with regard to a living body compared to light emission.
As molecular imaging has been actively researched, leading edge research using a fluorescence phenomenon has been carried out. Fluorescence can be readily implemented as a system for utilizing fluorescence can be implemented with simpler devices, such as an excitation light source, a band-pass filter, and a photodetector, than other detection devices. Thus, fluorescence technology may be cost-effective. In particular, when a fluorescence material having an emission signal in the visible light region from 400 to 700 nm is used, observation with the naked eye is available, and the penetration power with respect to the skin is desirable. Thus, a medical use of such fluorescence materials is increasing.
Fluorescence signals have poor SNR and relatively limited sensitivity. Emitted fluorescence signals have relatively high intensity, but fluorescence intensity decreases due to optical phenomena such as the scattering, absorption and so on which may occur when fluorescence signals in the visible light region are generated inside a living body. In order to resolve these problems, research on the development of near-infrared fluorescence materials having emitted signals in the rear-infrared region is being actively carried out because near-infrared light in the 780 to 2000 nm region has desirable penetration power characteristics compared to the visible light in the living body. Furthermore, due to the advantage of acquiring a signal related to depth information, an examination method applied to preclinical and clinical trials is under development.
As a method used in preclinical trials, a material that is mixed with a fluorescence material and a target probe which can be targeted at a disease is developed and is injected through intravenous injection. Then morphological characteristics of a tumor can be observed and the progress of the treatment is carried out. Also, this method can be widely used to evaluate clinical characteristics related to soft tissues. As a representative agent, indocyanine green (ICG), a near-infrared fluorescence agent approved by the FDA, is used as a vascular contrast medium for determining the extent of circulation in blood vessels. ICG is recently used to determine locations of sentinel lymph nodes (SNs) indicative of the extent of metastasis of tumors in the case of a breast cancer patient prior to the lumpectomy.
However, in the case of the implementation of near-infrared fluorescence, a near-infrared band-pass filter and a photodetection device are additionally required. In addition, images devices may be needed to determine image information such as shape, location and strength of fluorescence. Due to these limitations related to the implementation of near-infrared fluorescent images, technical improvements in near-infrared fluorescence imaging may be needed.